The present invention relates to optical transmission equipment and a method for controlling the optical transmission equipment. More particularly, the present invention relates to optical transmission equipment for an optical transmission system for multiplexing and transmitting plural signal lights, and to a method for controlling the optical transmission equipment.
As a dispersion compensation method, there is a control method for reducing signal errors. This method changes the dispersion value by a variable dispersion compensator when a signal error occurs due to dispersion changes resulting from the change in the transmission line characteristics or other factors. In this way, the method controls the dispersion value to fall within the dispersion tolerance range of an optical receiver.
JP-A 2003-258726 describes an optical receiving apparatus for detecting an uncorrected error in a code error correction circuit in the change of the transmission line dispersion, and controlling the amount of dispersion of a variable dispersion compensator upon detection of an uncorrected error.
However, according to JP-A 2003-258726, since the control is performed upon occurrence of the signal error, the dispersion tolerance remains reduced for other receivers in which no signal error occurs. As a result, there is no consideration of reducing the rate of further occurrence of errors in the change of the transmission line dispersion.